Gas turbine engines typically include a compressor section, a combustor section and a turbine section. The compressor section and the turbine section each have airfoils including rotating blades and stationary vanes. It may be desirable to provide a cooling (or heating in the case of the compressor section) airflow through the airfoils due to the relatively great temperatures at which they are operated. In that regard, the airfoils may include outer walls along with internal ribs or walls that form internal air passages through which a cooling airflow may flow. Because the outer walls are exposed to relatively hot air, they may experience greater thermal expansion than the internal ribs or walls. Such difference in thermal expansion undesirably results in compressive and tensile stress experienced between the outer walls and the internal ribs or walls.